Wild parsnip (Pastinaca sativa) plants are rising towards their full height and blooms are beginning to appear in southern Ohio. Landscape managers and gardeners should exercise extreme caution around this non-native invasive plant; the plant's juices can cause phytophotodermatitis (a.k.a. Berloque dermatitis). If plant juices contact skin and the skin is then exposed to sunlight (specifically ultraviolet light), severe blistering can occur, as well as skin discoloration that may last several months.
This Eurasian native can grow to impressive heights topping 8'. The umbellate flower arrangement looks like an upside-down umbrella; a characteristic shared by all members of the carrot family (Apiaceae (= Umbelliferae)). The umbels on wild parsnip are topped with tiny yellow flowers. Leaves are alternate, pinnately compound, branched, and have saw-toothed edges. Each leaf has 5 -15 ovate to oblong leaflets with variable toothed edges and deep lobes. Mature plants will produce a single, thick, deeply grooved, greenish-yellow stem that sprouts lateral branches topped with hundreds of clusters of the umbellate flowers.
Wild parsnip grows primarily as a biennial with a two season life cycle; however, flowering plants may occasionally behave as a perennial by surviving multiple years. Plants typically spend the first year as rosettes with leaves confined to growing from a short stem only a few inches above the ground. While in this stage, the plant produces a long, thick taproot. Wild parsnip is a prolific seed producer, and this is the primary means by which the plant spreads. The toxic nature of the sap makes mechanical control of wild parsnip problematic. Plants are susceptible to glyphosate (e.g. Roundup) which may be the safest approach to controlling this non-native invasive weed.